Pushchairs are currently widely used being provided with a frame with telescopic closure, which can be folded also along its height so as to assume a very limited size once folded.
These frames are usually formed by two front posts and two rear posts, which are associated in a downward region with respective wheels and are kinematically connected to each other by way of articulation structures, and by two upper posts that act as handles (commonly known as handle tubes), each of which slidingly engages a respective seat that is generally provided on the articulation structures in order to be able to pass from an extended position for use to a retracted folding position, by way of a downward translational motion.
Pushchairs are also currently commercially available being provided with a seat, which is provided with a back that has, at its sides, lateral wings, usually made of fabric, that are designed to be coupled to the handle tubes in order to achieve the dual advantage of a “sleep” configuration, i.e., in which the back is lowered, said configuration being more protected thanks to the covering action performed by such lateral wings, and of an adjustment of the back, which is achieved by using the coupling of the back to the handle tubes by means of strap systems that are integrated in the seat and are structurally far simpler, lighter, and more inexpensive than conventional adjustment systems that provide for racks and rigid back structures.
However, seats of this type cannot be applied to frames with telescopic closure, since the coupling of the lateral wings to the handle tubes would hinder free translational motion of the handle tubes during folding of the pushchair.